The implications of this admission should be huge to the majority of evangelical churches. In short, Willow Creek has admitted that they way they did discipleship, in which they invested millions and which they encouraged other churches to emulate, was flawed. And yet large numbers of megachurches and wanna-be-megachurches subscribe to this theory.
This deserves a much more thorough treatment on my part but I'd be interested to hear some thoughts on this.